Coiling an Einstein

17. October 2006

By targeted stimulation of certain brain regions motoric and mental abilities can be improved, at least temporarily. Transcranial magnetic stimulation assists the therapy of neurological dysfunctions - and not only that.

The reports of Allan Snyder from the Australian "Centre for the Mind" at Canberra and Alvaro Pascual-Leone from Harvard Medical School Boston sound almost too good to be true, talking about the waking of creative abilities and of a significant increase of memory, those proven by "blinded" experiments without use of any medication or surgery. The scientists just put a magnetic coil directly on the head's skin, thus being able to inhibit or stimulate particular targeted regions of the brain. Whether it is possible to evoke hidden insular abilities and extraordinary performances with the technology of transcranial magnetic stimulation (TMS), is yet controversial.

Actually an "old hat"

However, it is a fact, that physicians are using this technology on neurological dysfunctions in many ways and with good success. Despite that it is an "old hat". More than 100 years ago, the French physician Arsène d' Arsonval already tried to induce a flow of electricity in the brain by applying an electromagnetic coil to the head. Today, computer programs of the Fraunhofer Institute for Applied Information Technology, help positioning those magnetic coils exactly on certain regions of the brain by magnetic resonance shots. This way, targeted regions of the brain can be stimulated or inhibited by pulsed magnetic fields, the induction taking between 200 and 600 milliseconds and reaching a field intensity of 2.5 Tesla max. This is about a hundredfold stronger than for example a magnet you use to pin notes in your office.

Help through depression, apoplexia and tinnitus

Especially with the treatment of depressions, TMS has proven to be successful. In the British Journal of Psychiatry, Michael Wagner of Bonn University reports of good experience with TMS respectively the "Elektrokrampf-Therapie" EKT (electro-convulsion therapy). He treated 30 patients with severe depression, each one of them barely treatable with psychotherapy or drugs. Contrary to EKT, where electric impulses are conducted directly through the head, magnetic stimulation does not create any blackouts.

Similar studies by Frank Padberg of Munich University and others confirm the successful treatment of depressive patients with TMS.

But also with other neurological dysfunctions the targeted stimulation of selected brain regions is of help. Christian Plewnia of the Tuebingen University and Peter Eichhammer, Regensburg, published reports on tinnitus – treating patients suffering from noises in their ears. After stimulation, their suffering was at least alleviated, in several cases it even vanished.

The coil also helps with rehabilitation of apoplexia patients. Two articles, recently published in Lancet Neurology (Friedhelm Hummel, University of Hamburg) and Stroke from the Pascual-Leone group, describe that the use of TMS on intact brain hemisphere enables a faster return of motoric abilities than a "pseudo-stimulation" does.

Perhaps the effect of induced "neurone blaze" is very similar to those produced by long-term training. A co-operation of Hubert Dinse and Martin Tegenthoff of the Ruhr University Bochum clearly shows results. According to a report in PLOS Biology , the sensitivity of the index finger was improved within minutes with according pulses and this to a point beyond anything possible except after an accordingly extensive training.

TMS for a sharp view

Last but not least you can simulate eye muscle movement with TMS. Christian Ruff and his colleagues at the University College in London gave it a shot. AS they wrote in the August edition of Current Biology , the impulses lead – via the frontal cortex, responsible for eye movement – to an activation in the visual cortex. The contrast acuity of a view from the corner of the eye increased without moving the eye.

Despite its many applications, transcranial magnetic stimulation still is an experimental technology with only a few reliable larger studies available. So far it seems, that mental abilities can be improved, at least temporarily. The American Ministry of Defense supports studies about the possibility whether coils in the helmets can suppress a soldier's fatigue. Which parts of the brain may be stimulated is a thing yet to be decided in the future, not only by neurologists, but also the ethics committee and politicians.